Methods Plasma BNP concentration was measured by radioimmunoassay in asymptomatic heart failure patients(aSHF,n=21),symptomatic heart failure patients(SHF,n=42) and normal controls(n=18).

• 方法选择老年无症状性心力衰竭患者21例(aSHF组)和老年症状性心力衰竭患者42例(SHF组),另选18例健康老年人作为对照组,采用放射免疫分析法测定各组血浆BNP水平;